Carburettor heat reduces the air density of the air entering the engine. Consequently, the mass flow decreases and so does engine performance. Due to the decrease of engine power, carburettor heat is normally not used during hover, take-off and climb power settings.

Especially, important when taking-off from short fields, you want all the power your engine has to offer, as carb heat "robs" your engine of some power.

When the carburettor heat is applied in a hover, you should observe a loss of power. Because, the hot air is less dense compared to the cooler, ambient air, leading to a reduction in engine performance. In a hover, where precise power control is critical, this loss of power will be noticeable and can affect the ability to maintain a stable hover.